This invention concerns a new and efficient process for producing liquid nitrogen.
Liquid nitrogen is normally produced as a by-product of oxygen production. While there are sizable market demands for nitrogen by itself, in fields such as glass making, chemical inverting, electronics, and food preparation, these are end demands for the gas product, and the liquid form is merely a convenience for transportation and storage.
Large or stand alone demands for nitrogen gas are conventionally supplied by nitrogen gas generators, which often involve cryogenic distillation but produce no meaningful amounts of nitrogen in liquid form. When there is a large demand for the liquid form, without the simultaneous requirement of oxygen, nitrogen gas generators are typically coupled with a separate nitrogen liquefaction unit to fulfill this requirement.